Vehicles such as passenger cars, vans, buses, trucks, trains and airplanes generally may have headliners mounted inside the passenger compartment for providing an aesthetic covering for the inside of the sheet metal roof and/or framework under which they may be mounted. Headliners may also be provided for sound absorption, energy absorption and/or concealment of electrical wiring and HVAC ducting and vents.
Such headliners are generally constructed of multiple layers of material joined together and mounted to the roof sheet metal and/or associated framework. Such headliners are often made of materials, such as particleboard, fiberboard, formed plastic, fabric, and foam. For motor vehicles, such headliners may not however meet the requisite Federal head impact compliance standards without additional components being affixed thereon.
More recently, vehicles have become increasingly complex, particularly overhead systems, being equipped with an ever-expanding array of devices. Some of these devices are included for safety, for instance, side air bags and energy absorbing components, while other devices may be included primarily for pleasure, for instance, infotainment systems and elaborate climate control systems. This has lead to complex assemblies called “overhead systems” which include a headliner outfitted with ducting, speakers, wiring harnesses, energy absorbers, consoles, electronic modules and air bags.
The National Highway Traffic Safety Administration's (NHTSA) Federal Motor Vehicle Safety Standard 201(FMVSS201U), entitled “Occupant Protection in Interior Impact,” defines the criteria for upper interior impact protection of an occupant in a motor vehicle. Even with airbags, the vehicle occupant may impact the pillars, roof siderails, windshield (front) header and rear header resulting in passenger car occupant injuries. Head impact with the overhead system may be the cause of many moderate to critical or even fatal passenger car occupant injuries. A variety of constructions have been evaluated to provide compliance, however, most add further complexity and cost to the overhead system by adding multiple components and additional assembly labor and tooling.
It may therefore be desirable to provide a molded energy absorber made of a tunable and relatively lightweight material that only requires attachment to the back surface of a headliner or to the underside of the roof structure.
The Federal Government mandates impact testing and compliance under MVSS 201U to provide vehicles that can protect an occupant from high impact forces. Various components of the overhead system may be impacted at 15 mph with a free motion head form and must exhibit a head injury criterion (HIC) of less than 1000. In particular, the front header, left and right side rails and rear header areas must be compliant.